The International Classification of Mental and Behavioural Disorders 10th revision (ICD-10) medical classification system was published by the World Health Organization (WHO) in 1992.1

ICD-10 refers to attention-deficit hyperactivity disorder (ADHD) as hyperkinetic disorder (HKD), a term widely used in Europe and included in European clinical guidelines developed with the European Network for Hyperkinetic Disorders (EUNETHYDIS).2

This classification system defines HKD as a persistent and severe impairment of psychological development, characterised by “early onset; a combination of overactive, poorly modulated behaviour with marked inattention and lack of persistent task involvement; and pervasiveness, over situations and persistence over time of these behavioural characteristics”.1

Overview of the ICD-10 medical classification system for ADHD1

The main symptoms of HKD are impaired attention and overactivity. Both are necessary for diagnosis

Impaired attention – manifested by a lack of persistent task involvement and tendency to move from one activity to another without completion

ICD-10 also lists symptoms characteristic of children with HKD, but not necessary or sufficient for diagnosis:1

Disinhibition in social relationships

Recklessness in dangerous situations

Non-adherence to social norms (interrupting, intruding on others, prematurely answering questions, difficulty in waiting in turn).

Note that deficits in persistence and attention should be diagnosed only if they are excessive for the child’s age and IQ; and overactivity should be considered in the context of what is expected in the situation and by comparison with other children of the same age and IQ.1

Caution is recommended in children of pre-school age, and only extreme levels of hyperactivity should lead to a diagnosis in these individuals.1

Adult diagnosis

Diagnosis of HKD may also be made in adult life using the same criteria; however, attention and activity must be judged with reference to developmentally appropriate norms.1